Updates `DEPLOY_ENVIRONMENT` variables on `auto_deploy:deploy` build

What does this MR do?

DEPLOY_ENVIRONMENT on auto_deploy:deploy was using incorrect environment variables (gstg, cny, gprd-cny), this commit fixes to use the right ones (gst,gprd-cny,gprd)

This was noticed on https://ops.gitlab.net/gitlab-org/release/tools/-/pipelines/518031 / https://ops.gitlab.net/gitlab-org/release/tools/-/jobs/3409391 which triggered an empty deployer pipeline https://ops.gitlab.net/gitlab-com/gl-infra/deployer/-/pipelines/518095